1. Field
The invention is in the field of thermocouple hygrometer or psychrometer probes adapted for in situ, soil-moisture-content measurements.
2. State of the Art
The problem of contamination of thermocouples in hygrometer or psychrometer probes used for water potential measurement has been recognized for many years. However, none of the available probes have permitted easy cleaning of the thermocouple after use. Typically, a heat shrunk, non-elastic, plastic boot has been used to permanently secure the usual thermocouple shield and protect the electrical lead connections to the thermocouple. Attempts have been made to friction fit the thermocouple shield upon the thermocouple block, but the shields have not been satisfactorily retained. Threading the shield and the thermocouple block together has proven too expensive. Attempts to provide elastic coupling of the shield and the thermocouple block have failed because the elastic material of the shield has not retained its elasticity after extended use, or has been a strong vapor sink, thereby adversely affecting thermocouple performance.